According to municipalities, government agencies, environmentalists and the public in general, odour and potential pollution sources emanating from livestock, for example, hog, dairy, feedlot and chicken, facilities are the main issues that the livestock industry needs to address in order to sustain its development. The most intense source of odour from livestock facilities occurs during manure handling and land application.
U.S. Pat. No. 1,915,240 teaches a sewage purification method which comprises mixing lime and ferric chloride with raw sewage, which deodorizes the waste and causes floc formation. The floc is then oxidized and sterilized before being allowed to settle for subsequent removal and dewatering.
U.S. Pat. Nos. 3,619,420 and 3,640,820 teach a sewage treatment process wherein treated sludge is converted to an active substance by heat treatment and returned to the sewage treatment tank, thereby improving the operational efficiency of the method.
U.S. Pat. No. 4,309,291 teaches a method of continuous flow flocculation and clarification wherein waste water is flocculated by subjecting the mixture to continuous, turbulent flow to and from a settling tank. Clarified effluent and settled flocculent are continuously discharged from the settling tank.
U.S. Pat. No. 4,111,800 teaches a process for treating municipal solid waste and raw sewage sludge wherein municipal waste is mixed with cellulose-containing solid waste.
U.S. Pat. No. 4,180,459 teaches a process of making agricultural products from organic sewage sludge comprising treating sewage sludge with FeCl3 and CaO from various sources, preferably from sugar refining for flocculation. It is of note that the sewage sludge is characterized as “acidic conditioned sludge” having a pH of between 3.0-5.7.
U.S. Pat. No. 4,209,393 teaches using coal as a sewage sludge additive rather than activated carbon.
U.S. Pat. No. 4,212,732 teaches a raw liquid waste treatment process wherein ash and activated carbon are added to raw sewage to promote settling of flocculent.
U.S. Pat. No. 4,670,158 teaches a method of wastewater treatment wherein lime and phosphoric acid are added to wastewater to promote flocculation. In this method, the pH of the wastewater is adjusted to be within 7.0-10.0, preferably 8.5-9.0 with phosphoric acid.
U.S. Pat. No. 5,698,110 teaches a deodorizing composition for treating animal waste comprising a mixture of lime and cellulose so that the waste can subsequently be used as fertilizer.
U.S. Pat. No. 5,897,785 teaches a process for treating animal waste wherein waste is diluted with water and exposed to radiation to eliminate pathogens. High charge, cationic polymers are then added to the waste such that polymerized solids are formed which are then separated from the waste.
U.S. Pat. No. 5,958,758 teaches a process for treating animal waste wherein sulfide-utilizing bacteria are added to the waste followed by the addition of organic digesting bacteria and lytic enzymes.
U.S. Pat. No. 6,033,570 teaches a process for the treatment of liquid hog manure in which cellulosic material is added to promote removal of solids from the liquid.
U.S. Pat. Nos. 6,039,875 and 6,214,230 teach the use of bacterially-generated polymers as coagulants for the removal of suspended solids from wastewater.